1. Field of the Invention
The present invention relates to a refrigerant evaporator which composes a refrigerant cycle of an air conditioner incorporating a refrigerant compressor and a refrigerant condenser.
2. Description of Related Art
As for air blowing from a refrigerant evaporator, uniformity of air blow temperature distribution has been recently demanded. To achieve this purpose, a method to distribute refrigerant evenly to plural refrigerant evaporation passages is available. One of such refrigerant evaporators is disclosed in Japanese Patent Application Laid-Open No. 4-155194 hereafter referred to as "App. No. 4-155194", in which refrigerant flows into plural refrigerant passages formed inside the refrigerant evaporator. A refrigerant distribution pipe evenly distributes the refrigerant to plural refrigerant evaporation passages respectively, and a round-shaped throttle hole is disposed upstream of the refrigerant distribution pipe to create a liquid-gas mixed condition even with respect to the cross-section of the passages.
In the prior art, however, because the throttle causes a refrigerant passing noise, the size of the throttle should not be excessively small. Mainly due to gravitation, the gas ingredient flows in the refrigerant passage at the upper side of the refrigerant distribution pipe while liquid ingredient flows in the refrigerant passage at the lower side of the refrigerant distribution pipe. Thus, the refrigerant flow is separated. It has been impractical to distribute the refrigerant evenly inside the plural refrigerant passages of the refrigerant distribution pipe.
The farther the refrigerant goes from the inlet side to the back side of the plural refrigerant evaporation passages, the more difficult it is for the liquid refrigerant to flow. The closer the refrigerant comes to the inlet side, the more difficult it is for the liquid refrigerant to flow. Therefore, cooling performance between the air passing around the refrigerant evaporation passage at the inlet side and the air passing around the refrigerant evaporation passage at the back side differs, and blow temperature of the air passing around the refrigerant evaporation passage at the inlet side and blow temperature of the air passing around the refrigerant evaporation passage at the back side vary, which causes uneven distribution of blow temperature.